PROJECT SUMMARY There is consensus among the scientific and clinical community about the pressing need to better manage pain and depression among older adults with advanced Alzheimer?s diseases and related dementia (ADRD). Research has established that pain and depressed mood are strongly associated among older adults generally, and this relationship has been documented over time in longitudinal studies. The few studies that have examined the extent of the association between pain and depressive symptoms among nursing home residents with advanced ADRD rely on small sample sizes from different countries, use a diversity of depression and pain measures, or lack longitudinal designs to examine bidirectional relationships over time. The purpose of the proposed project is: 1) to determine the prevalence and incidence of self-reported and observer-rated depressive symptoms and pain among a national sample of US nursing home residents with advanced ADRD, and 2) to test the bidirectional relationship between depressive symptoms and different indicators of pain over time in cohorts of advanced ADRD nursing home residents with and without treatment. The proposed research is innovative because it not only focuses on multiple sources of distress in a population that is understudied, it also involves the use of structural equation modeling (SEM) to explore the bidirectional relationship between a latent concept with measurement error and multiple indicators of pain. By the end of this research project, we will have documented the unmet end-of-life care need that the overlap of pain and depressive symptoms represents among NH residents with advanced ADRD nationally, and determined the strength of the bidirectional association between these symptoms over time for different pain indicators. These contributions represent the first step of a larger research program that includes the development of targeted palliative care services for this group, including assessments of the global experience of suffering by a multidisciplinary team and improved clinical management. Assessing the quality of end-of-life care in NHs is a research priority that is unlikely to be achieved if symptoms are approached in isolation. This work has the potential to quantify actionable outcomes in terms of suffering and distress in a growing clinical population.